Burner for the partial oxidation of liquid fuels which contain carbon

ABSTRACT

The burner has at least two fuel-carrying tubes which are arranged in parallel, the distance between adjacent fuel-carrying tubes being 5 to 30 cm. Each fuel-carrying tube is surrounded by a steam-carrying tube, which at its orifice end has a supply line for oxygen-containing gas. The steam-carrying tubes are surrounded by a common first cooling chamber through which cooling liquid is passed, the first cooling chamber constituting an annular chamber and extending into the area of the orifice ends of the steam-carrying tubes. Coaxial to the first cooling chamber a common second cooling chamber preferably is provided, which is surrounded by the first cooling chamber.

DESCRIPTION

This invention relates to a burner for the partial oxidation of liquid,carbonaceous fuel by means of steam and an oxygen-containing gas.

Burners of this kind, which are directed into a combustion chamber, areknown for instance from EP 0 127 273 B1, the U.S. Pat. No. 4,933,163 andEP 0 707 880 A1. From the last-mentioned publication it is also known todispose such burner at the entrance of an empty combustion chamber, theraw product gas produced being cleaned subsequently and being processedfor instance to obtain a synthesis gas.

It is the object underlying the invention to create a burner for thepartial oxidation of liquid fuels such as heavy oil, which burner issuited for high throughput capacities and at the same time allows aninexpensive operation. In accordance with the invention this is achievedin that at least two fuel-carrying tubes are arranged in parallel, thedistance between adjacent, fuel-carrying tubes being 5 to 30 cm, thateach fuel-carrying tube is surrounded by a steam-carrying tube, that theorifice end of each steam-carrying tube has a supply line foroxygen-containing gas, and that the steam-carrying tubes are surroundedby a common first cooling chamber through which cooling liquid ispassed, the first cooling chamber constituting an annular chamber andextending into the area of the orifice ends of the steam-carrying tubes.The number of fuel-carrying tubes usually lies in the range from 2 to 20and preferably from 3 to 12.

Due to the common first cooling chamber a compact, relatively simpleconstruction of the burner is obtained, at the same time a sufficientcooling of the area of the orifice ends of the steam-carrying tubes isensured, which tubes are exposed to the high temperatures in thecombustion chamber. At the point where the oxygen-containing gas meetsthe fuel local temperatures up to about 1700° C. occur. Coaxial to thefirst cooling chamber a common second cooling chamber is expedientlyprovided, which is surrounded by the first cooling chamber. It may berecommended to provide a connecting passage for cooling liquid betweenthe first and the second cooling chamber.

A further development of the burner consists in that inside the area ofthe first cooling chamber at least one passage for an insertable andremovable auxiliary burner is provided. This auxiliary burner may beused for instance only in the start-up phase of the gasificationoperation, and it is removed from the burner assembly during thecontinuous operation.

As liquid, carbonaceous fuel there may for instance be used heavy oil, apumpable slurry of granular coal or petroleum coke in water or in liquidhydrocarbons, as well as an emulsion of bitumen or asphalt in water. AsO₂-containing gas there is normally used technically pure oxygen oroxygen-enriched air, if the nitrogen content is not disturbing.

Embodiments of the burner will be explained with reference to thedrawing, wherein:

FIG. 1 shows a longitudinal section through the burner in a schematicrepresentation, sectioned along line I—I of FIG. 2, and

FIG. 2 shows a cross-section through the burner of FIG. 1, section edalong line II—II.

The burner 1 has a distribution chamber 2 for liquid fuel, here alsoreferred to as first distribution chamber. The liquid fuel is suppliedthrough the inletport 2 a and pressed out through the fuel-carryingtubes 3. In the present case, four fuel-carrying tubes 3 are connectedwith the distribution chamber 2, cf. FIG. 2, of which tubes two areshown in FIG. 1. Each tube 3 is coaxially surrounded by a steam-carryingtube 4. The conically tapered shape of the tubes 4 towards the orificeend 4 a is not absolutely necessary. The steam is supplied through aninlet 5 a and first of all enters a second distribution chamber 5,before it flows out through the tubes 4. In the orifice area 4 aatomized fuel and steam are mixed before the mixture leaves the burner.Through annular slots 6 a oxygen-containing gas is supplied to themixture, which gas is required for partial oxidation. Theoxygen-containing gas comes from a third distribution chamber 6 and issupplied through the inlet port 6 b.

In the central area of the burner 1 a cylindrical passage 8 is provided,into which e.g. an auxiliary burner, for instance for the start-upphase, can be inserted if necessary. When the auxiliary burner is nolonger used, it can be removed from the passage 8, and the passage canbe sealed by means of a lid not represented. The passage 8 is surroundedby a cylindrical wall 9, which is in contact with a cooling chamber 12.The cooling chamber 12, which constitutes an annular chamber andsurrounds the passage 8 and the cylinder wall 9, is referred to assecond cooling chamber. The first cooling chamber 11 rests against theinside of the burner housing la, which for instance has a cylindricalshape. The cooling liquid, e.g. water, is supplied through the inlet 11a and is discharged through the outlet 11 b. Between the first coolingchamber 11 and the second cooling chamber 12 the two connecting passages13 and 14 are provided, which each extend past a steam-carrying tube 4.For a better optical clarity the parts of the burner through whichcooling liquid flows are represented with dots. By means of notrepresented flow obstacles in the cooling chambers it is ensured thatthe cooling liquid preferably takes a flow path as it is necessary forthe desired temperatures. It is in particular ensured that the coolingeffect also sufficiently exists in the vicinity of the orifice area 4 aof the burner.

In the drawing, which represents the burner only schematically, spacersbetween the various parts were omitted, so as not to impair the clarityof the representation.

In the present case, four fuel-carrying tubes 3 and the associatedsteam-carrying tubes 4 are disposed inside the first cooling chamber 11,but the number of the tubes 3 with the associated tubes 4 can lie in therange between 2 and 20 and preferably 3 and 12. It may be recommended todispose these tubes in the area between the first and the second coolingchamber, and to provide a passage 8 for the auxiliary burner in thecentral area. This passage 8 is, however, not necessary in all cases.

What is claimed is:
 1. A burner for the partial oxidation of liquid,carbonaceous fuel by means of steam and an oxygen-containing gas,comprising at least two fuel-carrying tubes approximately disposed inparallel, the distance between adjacent fuel-carrying tubes being 5 to30 cm, wherein each fuel-carrying tube is surrounded by a steam-carryingtube, and each steam-carrying tube has a supply line foroxygen-containing gas at its orifice end, and the steam-carrying tubesare surrounded by a common first cooling chamber through which coolingliquid is passed, the first cooling chamber constituting an annularchamber and extending into the area of the orifice ends of thesteam-carrying tubes, wherein there is provided at least one passage foran insertable and removable auxiliary burner.
 2. The burner as claimedin claim 1, wherein coaxial to the first cooling chamber a common secondcooling chamber is disposed, which is surrounded by the first coolingchamber.
 3. The burner as claimed in claim 2, wherein between the firstand the second cooling chamber at least one connecting passage forcooling liquid is provided.
 4. The burner as claimed in claim 1 whereina first distribution chamber for liquid fuel is provided, with which thefurl-carrying tubes are connected.
 5. The burner as claimed in claim 1wherein a second distribution chamber for steam is provided, with whichthe steam-carrying tubes are connected.
 6. The burner as claimed inclaim 1, wherein a third distribution chamber for oxygen-containing gasis provided, with which the supply lines for oxygen-containing gas areconnected.
 7. The burner as claimed in claim 4, the wherein passage forthe auxiliary burner is surrounded by the second cooling chamber.